Anti-topoisomerase antibodies (ATA) are autoantibodies directed against topoisomerase and found in several diseases, most importantly scleroderma.
Anti Scl-70 antibodies (also called anti-topoisomerase I after the type I topoisomerase target[1]) is a type of antinuclear autoantibody seen mainly in diffuse systemic scleroderma, but is also seen the more limited form of systemic scleroderma called CREST syndrome.
[4] Anti-topoisomerase antibodies can be classified according to their immunoglobulin class (IgM, IgG or IgA).
IgG-ATA is found most frequently in scleroderma, with IgA being quite common but IgM very infrequent.
[13] In addition to HLA-DR, the protein tyrosine phosphatase, non-receptor type 22 (lymphoid) (1p13.2 - PTPN22), "CT/TT" genotype showed significant association with anti-topo I.